F-519920 
Figure 132.—Adults of the poplar borer, 
Saperda calcarata. 
trees in stands averaging between 7.5 and 28 cm d.b.h. Lake States infestations also 
tend to increase with a decrease in stand density. 
The best practice in the management of poplar in the Lake States apparently is to 
maintain well-shaded stands and then clearcut them at maturity. The removal of 
“brood trees” should also be helpful (388). 
The roundheaded appletree borer, S. candida F., occurs in Canada and 
throughout the Eastern United States. It is most serious as a pest of apple orchards, 
but it also breeds in mountain-ash, hawthorn, and serviceberry. The adult is 
brilliantly white except for three broad, brown, longitudinal stripes extending the 
full length of the back, and is from 15 to 20 mm long. Full-grown larvae are creamy 
white and about 30 mm long (562). 
Adults are present from June to September and deposit their eggs in slits cut in 
the bark at the base of living trees. They feed on ‘the foliage and sometimes on 
tender bark. The larvae feed beneath the bark for | year and then bore into the 
wood, making large excavations and riddling it. The presence of tendrils of frass on 
the bark or at the base of the tree 1s evidence of attack. Heavily infested trees may be 
killed in a single season. Two or more years are required to complete the life cycle. 
Keeping trees healthy is an effective preventive measure. Borers in high-value trees 
can be killed by injecting a fumigant into borer burrows. 
The linden borer, S. vestita Say, occurs in the Northeastern States and Canada. 
Its preferred host is basswood but it also attacks poplars. The adult is reddish 
brown, densely covered with prostrate, fine, olive-yellow hair, and is from 12 to 21 
mm long. The tips of the antennae are brown, and there are three small black spots 
on each wing cover. Adults feed on leaf petioles, the larger veins of leaves, and the 
bark of growing shoots, often killing the tips of infested branches. The larvae feed 
297 
